Which aero bike is actually the fastest? (video)

It is normal practice for a bike manufacturer to claim its aero bike is the fastest out there.

Clearly they can’t all be the fastest, so we decided to try and find out which one actually is. To do this, we teamed up with aerodynamic testing specialists WattShop and headed to Derby Velodrome to perform some testing in a controlled environment.

All the aero bikes we have here are leading models from their respective brands and all are WorldTour framesets used by the pros.

So far we have tested what we consider to be five of the most sought after aero bikes on the market. If demand is sufficient, we will perform a second round of testing with another batch of aero bikes and update the results on this page.

How we tested

We travelled to Derby Velodrome to perform aero testing on all the bikes in a controlled environment. This was done in a bid to quantitatively find out which of these bikes is the fastest.

Aero-testing specialists WattShop were on hand to help us record and interpret power data during our velodrome testing. Each bike was ridden at a target power of 380 watts.

The reason for this, is that this equated to a speed of roughly 45-48kph, which is considered the industry standard for aero testing.

At this speed, data is more consistent and repeatable than at lower velocities. Furthermore, this was a power output that was sustainable and reproducible for our test rider, national pursuit champion, Dan Bigham.

The WattShop software is able to interpret the power and speed data to give a drag coefficient for each bike. Slight differences in the power were accounted for using the WattShop software.

Watt Shop was on hand to help us record and interpret the data

Prior to each run, temperature, air pressure and system weight were recorded. A coefficient of rolling resistance was measured and calculated. By subtracting the watts required to overcome drivetrain friction and rolling resistance, we are left with the ‘aero watts’ – our comparative measure (the watts required to drag at 45kph).

These are presented for each bike for three different riding positions – the hoods, the drops and riding in a low aero position on the hoods.

For consistency, the bikes were set up in as close a riding position to each other as possible and the same wheels were used in all the bikes. The reason for this is that we wanted the variable to be the bike frame itself and not the rider or wheelset.

The wheels were a set of Fast Forward F9Rs with a PowerTap G3 rear hub for power measurement. For reference, 1W equates to 0.1 second per kilometre, as a rule of thumb.

All the bikes were fitted with the same PowerTap G3 Fast Forward F9R wheelset

Results and Conclusion

The raison d’être for aero bikes is without question how aerodynamic they are.

The purpose of this test is to simply rank the bikes on aerodynamic performance. For consideration of other factors such as comfort, specification, ride quality and value, feel free to click on the respective individual bike reviews.

Aerodynamics appears to be progressing with the oldest design in our test, the Propel, appearing slowest.

The Canyon Aeroad is worthy of mention – it may not be the fastest but for around £3,000 you can purchase an Ultegra-equipped version with the same frame and aerodynamics.

Limitations should also be pointed out – testing in an indoor velodrome has the advantage of good run repeatability and consistency. The main disadvantage is that wind yaw angles can be lower than those that can be experienced on the road, particularly when riding at slower speeds.

While every effort was made to get the bikes in the same riding position, the Canyon had a slight advantage with 41cm-wide bar while the others all had 42cm.

It should also be pointed out that slightly different handlebar shapes will undoubtedly create slight differences, hence the decision to test each bike in three positions. Coefficient of variance was very good lap to lap, of around 0.8-1.3 per cent across all test runs. Test velocity was typically 48kph (13.3m/s) and air density was 1.1663kg/m3.

In answer to the question which sprinter has the fastest bike, it would appear the Specialized and Trek riders do, although Cav shouldn’t lose too much heart as this was measured to only be a couple of watts while in an aero position at 45kph.

It was, however, very close between the Madone and Venge ViAS. Although we did repeat runs, the results are so close they are potentially within the realm of experimental error with both bikes representing the fastest available.

The Madone wins out because in addition to class-leading aerodynamics it is also comfortable thanks to the IsoSpeed decoupler. It is also impressively light for such an aero design at almost a kilo lighter than the Venge.

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